The prior art is replete with abrasive devices made out of some substrate and having abrasive particles or grit secured thereto. See for example: U.S. Letters Pat. No. 3,963,458 (Gladstone et al.), U.S. Pat. No. 3,997,302 (Supkis), and U.S. Pat. No. 4,027,435 (Malloy). One of the most common abrasive devices comprises a paper or plastic sheet or disk on which a plurality of abrasive particles are adhesively secured. Other types of abrasive devices comprise fabrics or non-wovens having a filament structure on which abrasive particles are adhesively secured. See for example, U.S. Letters Pat. No. 6,287,353 (Celikkaya) which discloses an open lofty polymer, e.g., polyester, polyamide, and polyaramid, non-woven filament or fiber structure having abrasive grains distributed throughout the structure and adherently bonded therein by an organic binder.
U.S. Letters Pat. No.3,947,169 discloses abrasive-filled plastic rods or tubes as a man-made alternative to natural abrasive filaments. The apparatus of that patent is in the form of extrusion cylinders which are arranged for receiving plastic molding pellets. The pellets may be thermoplastic or thermosetting, are rendered to a semi-liquid state in the apparatus and then a filler, grit, is introduced into the plastic so that the liquid or semi-liquid state of the plastic envelops the filler.
Other arrangements for applying an abrasive coating on fibers or filaments are shown in the following U.S. Letters Pat. No. 4,715,150 (Takeuchi, et al.); U.S. Pat. No. 5,491,025 (Pihl, et al.); U.S. Pat. No. 5,571,296 (Barber, Jr., et al.); U.S. Pat. No. 5,591,239 (Larson, et al.); U.S. Pat. No. 5,616,411 (Barber, et al.); and U.S. Pat. No. 5,863,305 (Beardsley, et al.).
While the prior art abrasive devices making use of abrasive fibers and apparatus and methods for producing them are generally suitable for their intended purposes, they still leave much to be desired from one or more of various standpoints, e.g., ease of manufacture, ease of incorporation into other abrasive products, fineness of abrasiveness, ease and effectiveness of use, etc.